I'm installing Bruce Engineered flooring on a concrete slab that was poured back in July using Bruce Equilizer glue. There are some non-flat spots. One area next to the wall dips 3/8" and another section has a low spot of 1/4".

Bruce says to use Armstrong leveling compound (S-194) with additive (S-195) to flatten the floor.

My contractor has expressed concern with this because he believes that the leveling compound will crack and pulverize over time (10+ years).

My question to you all: have you ever experienced leveling compound cracking and pulverizing? How has your experience with the Armstrong products (S-195/S-194) been?

BTW My contractor suggests glueing properly sized cedar shims to the slab and then laying the floor over this. This seems dubious at best.

Thanks in advance for any thoughts you have on this.
Steve

Edited By Administration:

Please see TOS. Thanks

Your contractor is an uneducated idiot!

The Armstrong compound works great as long as you use the latex additive.

ARDEX SD-F
Mapei PlaniPatch
Webcrete
and a couple of others have basically the same stuff.

It will not crack or turn to dust, if you apply as directed. Go look at the PSI rating, once these products are cured!!

You must use a cementious based patching compound. Even the starch based fillers/levelers ( Vitex and Fixall ) used by vinyl and carpet guys will not powder especially when used with the latex additive. All will crack or break up if you drive screws or nails into them. Follow Floorguys advice.

Here are some floor prep pictures...



Here I am checking the flatness of the concrete with my 10 foot straight edge.
Looks a little off, would you say?










Here I drug the first screed across the floor to fill the low spot. That is a full 5 gallon bucket of mud right there...









Next I finished up the rest of the gully, dragging back towards the other, to fill in...







Next, I skim coated the entire surface, to encapsulate any contaminates I couldn't scrape off the concrete...

Here it is finished and ready for wood.







Here, I measured out from the wall and popped my starting line. Then spread the adhesive. I work from the line back to the wall.







Moving right along, across the room...








Here it is finished...








Does that give you an idea of how it all happens?

Perry, you are a true PRO in the direct to concrete prefinished flooring installs. I rarely see anyone pay as much attention to the details as you. You probably deserve more than you are paid! Not too many around like you! Most just sweep and start spreading glue. You're a credit to the profession.

Nice Perry!

Btw, the original poster had referenced another online retailer which I had to delete. They seemed to think the same thing about using floor patching compounds. Like it says on our home page:

Everybody says something different. [url=http://www.hardwoodinstaller.com/hardwoodinstaller/everybody.htm]Who to believe?
[/url]

Quit it, you guys! I'm just doing my job and what I'm being paid for.


I can't believe I'm one of few who follow manufacturers requirements.

A picture says a thousand words and most DIY'ers are clueless about what it takes to do the most important part of the whole job, The Floor Prep!

Floorguy: Thank you very much for taking the time to post a reply and those pictures!! It is a great sense of relief to have this issue resolved. BTW, I noticed your picture has you at full draw. I hope your season's gone well. With the work on the addition I'm having put on (I'm doing painting, flooring, and some other work) I've only taken the time to take my son (10 yr) out for the youth days (duck and deer).

Ken: Sorry about posting the "other" online vendor!! Thanks for just deleting that line (actually I couldn't figure out what you had changed until you posted) instead of deleting the whole post. I really appreciate you providing this forum.

[quote="Floorguy"]Here are some floor prep pictures...

Here I am checking the flatness of the concrete with my 10 foot straight edge.
Looks a little off, would you say?

Hi Floorguy,

One question regarding flatness. If you installing 3/4" CDX plywood over the concrete as a subfloor and you came across a dip like the one in you picture, would you still level dips like this? Or would the plywood subfloor create enough of a flat surface to apply 3/4" flooring?

Thanks, Stan

¾" is pretty stout. If the plywood is sitting on a high spot, and the sheets around in a vally, your going to have concerns.


I've seen them use all kinds of things under the plywood to shim the low spots and fill the low spots. Even sand & dirt.

Concerns, yes.
But let us consider this; direction issues aside, 3/4 in plywood could conceivably span a 16- 19 inch low spot in the slab and create a situation indistinguishable from any floor nailed over wood-frame construction.

Just something to think about.

I think Chuck hits on what I was getting at. Even if a slab is basically flat with no high spots, there are always dips, or depressions if you will, randomly throughout the floor. In my case, the dips are slight, with the the largest begining 12"x10" and 1/8" deep. I guess a best case senario would be to fill the dips with self leveling compound, but I also think by filling the dip in the slab with #15 or #30 felt to bring the dip up would work, too. At the same time, 3/4 plywood subfloor is stout enough to make and dip, as Chuck says, indistinguishable.

Thanks agian for the input.

Structurally, you're correct. 3/4" ply will span depressions. But consider this. The plywood will emit a hollow sound over the areas where it is not in contact with the concrete. And that sound will still be present after the wood flooring has been laid. Now if this is acceptable to you, then fine. My preference would be to fill the valleys. What if one of the low spots is a a joint in the plywood? You will then have a depression in the plywood when you nail/glue it down. So what is better? Fill it before installing the ply or after? You can do it both ways but I think it is easier to fill the lows before installing the plywood. Just my opinion.